Reaction between [Ni(cyclam)]2+ and [W(CN)8]4− leads to the formation of a 3D diamond-like network [Ni(cyclam)]2[W(CN)8]·3.5H2O (1). The structure is characterised by a network of intersecting channels of 3–4 Å in diameter, filled with crystallisationwater, most of which is released upon drying in air, causing the crystals to collapse. Analogous compound [Ni(cyclam)]2[Nb(CN)8]·3.5H2O (2), based on paramagnetic Nb(IV), could only be obtained as a powder, due to the decomposition of the [Nb(CN)8]4− complex under slow diffusion conditions. It shows long-range magnetic ordering with TC = 11.8 K and magnetic hysteresis at 2 K. These properties are lost upon drying in air. After rehydration differently shaped hysteresis appears, which together with AC susceptibility measurements suggests the formation of a multiphase system. Subsequent dehydration–rehydration experiments show partial reversibility.